Cardiac MR PET CT Program, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Radiology, Massachusetts General Hospital, Boston, MA, USA.
Cardiac MR PET CT Program, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
J Cardiovasc Comput Tomogr. 2017 Jul-Aug;11(4):249-257. doi: 10.1016/j.jcct.2017.03.002. Epub 2017 Mar 22.
Coronary computed tomography angiography (coronary CTA) allows efficient triage of low to intermediate risk patients with suspected acute coronary syndrome (ACS) in the emergency department (ED). Techniques for coronary CTA acquisition in the ED continue to evolve with the establishment of standardized scan protocols and the introduction of newer generations of CT hardware.
To evaluate qualitative and quantitative image quality and radiation dose exposure of coronary CTA acquired on 2nd versus 3rd generation dual source CT (DSCT) scanners using a standardized institutional scan protocol designed for the ED.
A retrospective observational case-control study was performed of 246 ED patients referred to coronary CTA with suspicion of ACS (56.5% male; mean age 53.3 ± 11.6 years) between October 2013 and August 2015.123 consecutive patients were scanned on 3rd generation DSCT, and a cohort of 123 patients matched by age, BMI and heart rate were identified who had undergone 2nd generation DSCT imaging utilizing the same standard clinical protocol. Qualitative and quantitative image quality parameters and radiation exposures were evaluated.
Qualitative image quality was significantly higher using 3rd generation DSCT as compared to 2nd generation (p < 0.001). Mean attenuation in the proximal coronary arteries was also significantly higher on 3rd generation DSCT than for 2nd generation (586 HU vs. 426 HU in the left main coronary artery (LM), p < 0.001). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values, however, were lower in 3rd generation DSCT than 2nd generation (SNR 11.2 [9.9-13.4] vs 13.5 [11.0-15.5] and CNR 12.4 [10.9-14.8] vs 15.2 [12.8-17.9] in the LM, p < 0.001). Median effective dose was also lower for 3rd generation DSCT than for 2nd generation (2.9 [2.3-5.0] mSv and 3.7 mSv [2.5-5.7], respectively) although this trend did not reach statistical significance (p = 0.065).
Qualitative image quality and mean CT attenuation values of the assessed coronary segments were significantly higher using 3rd generation DSCT. SNR and CNR were lower on 3rd generation DSCT, however this was accompanied by a trend toward lower radiation dose exposure when using the same standard institutional protocol.
冠状动脉计算机断层血管造影术（冠状动脉 CTA）可在急诊科（ED）对疑似急性冠状动脉综合征（ACS）的低至中度风险患者进行有效分诊。ED 中冠状动脉 CTA 采集技术不断发展，建立了标准化扫描方案，并引入了新一代 CT 硬件。
使用专为 ED 设计的标准化机构扫描方案，评估第二代和第三代双源 CT（DSCT）扫描仪上获得的冠状动脉 CTA 的定性和定量图像质量和辐射剂量暴露。
回顾性观察性病例对照研究纳入 2013 年 10 月至 2015 年 8 月期间因疑似 ACS 而接受冠状动脉 CTA 检查的 246 例 ED 患者（56.5%为男性；平均年龄 53.3±11.6 岁）。123 例连续患者接受第三代 DSCT 扫描，按年龄、BMI 和心率匹配的 123 例患者确定为接受第二代 DSCT 成像，使用相同的标准临床方案。评估定性和定量图像质量参数以及辐射暴露情况。
与第二代相比，第三代 DSCT 的定性图像质量显著提高（p<0.001）。近端冠状动脉的平均衰减也明显高于第二代（左主干冠状动脉（LM）分别为 586 HU 和 426 HU，p<0.001）。然而，第三代 DSCT 的信噪比（SNR）和对比噪声比（CNR）值低于第二代（LM 分别为 11.2[9.9-13.4]和 13.5[11.0-15.5]，12.4[10.9-14.8]和 15.2[12.8-17.9]，p<0.001）。第三代 DSCT 的中位有效剂量也低于第二代（分别为 2.9[2.3-5.0] mSv 和 3.7 mSv[2.5-5.7]，尽管这一趋势没有统计学意义（p=0.065）。
使用第三代 DSCT 可显著提高评估冠状动脉节段的定性图像质量和平均 CT 衰减值。然而，第三代 DSCT 的 SNR 和 CNR 较低，但使用相同的标准机构协议时，辐射剂量暴露呈下降趋势。
